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<ol class="chapter"><li class="chapter-item expanded affix "><a href="../index.html">Introdução</a></li><li class="chapter-item expanded "><a href="../getting_started/index.html"><strong aria-hidden="true">1.</strong> Introdução Rápida as Plataformas</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../getting_started/desktop.html"><strong aria-hidden="true">1.1.</strong> Desktop</a></li><li class="chapter-item expanded "><a href="../getting_started/web.html"><strong aria-hidden="true">1.2.</strong> Web</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../getting_started/hot_reload.html"><strong aria-hidden="true">1.2.1.</strong> Hot Reload</a></li></ol></li><li class="chapter-item expanded "><a href="../getting_started/ssr.html"><strong aria-hidden="true">1.3.</strong> Renderização por Servidor</a></li><li class="chapter-item expanded "><a href="../getting_started/tui.html"><strong aria-hidden="true">1.4.</strong> Interface do Terminal</a></li><li class="chapter-item expanded "><a href="../getting_started/mobile.html"><strong aria-hidden="true">1.5.</strong> Móvel</a></li></ol></li><li class="chapter-item expanded "><a href="../describing_ui/index.html"><strong aria-hidden="true">2.</strong> Descrevendo a Interface do Usuário</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../describing_ui/special_attributes.html"><strong aria-hidden="true">2.1.</strong> Atributos Especiais</a></li><li class="chapter-item expanded "><a href="../describing_ui/components.html"><strong aria-hidden="true">2.2.</strong> Componentes</a></li><li class="chapter-item expanded "><a href="../describing_ui/component_props.html"><strong aria-hidden="true">2.3.</strong> Props</a></li><li class="chapter-item expanded "><a href="../describing_ui/component_children.html"><strong aria-hidden="true">2.4.</strong> Componente Filho</a></li></ol></li><li class="chapter-item expanded "><a href="../interactivity/index.html"><strong aria-hidden="true">3.</strong> Interatividade</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../interactivity/event_handlers.html"><strong aria-hidden="true">3.1.</strong> Manipuladores de Eventos</a></li><li class="chapter-item expanded "><a href="../interactivity/hooks.html"><strong aria-hidden="true">3.2.</strong> Hooks & Estado de Componentes</a></li><li class="chapter-item expanded "><a href="../interactivity/user_input.html"><strong aria-hidden="true">3.3.</strong> Entradas do Usuário</a></li><li class="chapter-item expanded "><a href="../interactivity/sharing_state.html"><strong aria-hidden="true">3.4.</strong> Estado Compartilhado</a></li><li class="chapter-item expanded "><a href="../interactivity/custom_hooks.html"><strong aria-hidden="true">3.5.</strong> Hooks Personalizados</a></li><li class="chapter-item expanded "><a href="../interactivity/dynamic_rendering.html"><strong aria-hidden="true">3.6.</strong> Renderização Dinâmica</a></li><li class="chapter-item expanded "><a href="../interactivity/roteador.html"><strong aria-hidden="true">3.7.</strong> Roteamento</a></li></ol></li><li class="chapter-item expanded "><a href="../async/index.html"><strong aria-hidden="true">4.</strong> Assincronia</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../async/use_future.html"><strong aria-hidden="true">4.1.</strong> UseFuture</a></li><li class="chapter-item expanded "><a href="../async/use_coroutine.html"><strong aria-hidden="true">4.2.</strong> UseCoroutine</a></li><li class="chapter-item expanded "><a href="../async/spawn.html" class="active"><strong aria-hidden="true">4.3.</strong> Gerando Futures</a></li></ol></li><li class="chapter-item expanded "><a href="../best_practices/index.html"><strong aria-hidden="true">5.</strong> Práticas Recomendadas</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../best_practices/error_handling.html"><strong aria-hidden="true">5.1.</strong> Tratamento de erros</a></li><li class="chapter-item expanded "><a href="../best_practices/antipatterns.html"><strong aria-hidden="true">5.2.</strong> Antipadrões</a></li></ol></li><li class="chapter-item expanded "><a href="../publishing/index.html"><strong aria-hidden="true">6.</strong> Publicação</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../publishing/desktop.html"><strong aria-hidden="true">6.1.</strong> Desktop</a></li><li class="chapter-item expanded "><a href="../publishing/web.html"><strong aria-hidden="true">6.2.</strong> Web</a></li><li class="spacer"></li></ol></li><li class="chapter-item expanded "><a href="../custom_renderer/index.html"><strong aria-hidden="true">7.</strong> Renderizador Personalizado</a></li><li class="spacer"></li><li class="chapter-item expanded affix "><a href="../roadmap.html">Roteiro</a></li><li class="chapter-item expanded affix "><a href="../contributing.html">Contribuindo</a></li></ol>
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<h1 id="gerando-futures"><a class="header" href="#gerando-futures">Gerando Futures</a></h1>
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<p>Os <strong>"hooks"</strong> <code>use_future</code> e <code>use_coroutine</code> são úteis se você quiser gerar incondicionalmente o <code>Future</code>. Às vezes, porém, você desejará apenas gerar um <code>Future</code> em resposta a um evento, como um clique do mouse. Por exemplo, suponha que você precise enviar uma solicitação quando o usuário clicar em um botão "log in". Para isso, você pode usar <code>cx.spawn</code>:</p>
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<pre><pre class="playground"><code class="language-rust edition2018">
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<span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span> let logged_in = use_state(cx, || false);
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let log_in = move |_| {
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cx.spawn({
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let logged_in = logged_in.to_owned();
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async move {
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let resp = reqwest::Client::new()
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.post("http://example.com/login")
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.send()
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.await;
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match resp {
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Ok(_data) => {
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println!("Login successful!");
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logged_in.set(true);
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}
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Err(_err) => {
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println!(
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"Login failed - you need a login server running on localhost:8080."
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)
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}
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}
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}
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});
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};
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cx.render(rsx! {
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button {
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onclick: log_in,
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"Login",
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}
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})
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<span class="boring">}
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</span></code></pre></pre>
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<blockquote>
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<p>Nota: <code>spawn</code> sempre gerará um <em>novo</em> <code>Future</code>. Você provavelmente não quer chamá-lo em cada renderização.</p>
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</blockquote>
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<p>O <code>Future</code> deve ser <code>'static</code> – então quaisquer valores capturados pela tarefa não podem carregar nenhuma referência a <code>cx</code>, como um <code>UseState</code>.</p>
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<p>No entanto, como você normalmente precisa de uma maneira de atualizar o valor de um gancho, você pode usar <code>to_owned</code> para criar um clone do <em>handle</em> do <em>hook</em>. Você pode então usar esse clone no encerramento assíncrono.</p>
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<p>Para tornar isso um pouco menos detalhado, o Dioxus exporta a macro <code>to_owned!</code> que criará uma ligação como mostrado acima, o que pode ser bastante útil ao lidar com muitos valores.</p>
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<pre><pre class="playground"><code class="language-rust edition2018">
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<span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span> use dioxus::hooks::to_owned;
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cx.spawn({
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to_owned![count, age, name, description];
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async move {
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// ...
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}
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});
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<span class="boring">}
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</span></code></pre></pre>
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<p>Calling <code>spawn</code> will give you a <code>JoinHandle</code> which lets you cancel or pause the future.</p>
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<h2 id="gerando-tarefas-do-tokio"><a class="header" href="#gerando-tarefas-do-tokio">Gerando Tarefas do Tokio</a></h2>
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<p>Às vezes, você pode querer gerar uma tarefa em segundo plano que precise de vários <em>threads</em> ou conversar com o hardware que pode bloquear o código do seu aplicativo. Nesses casos, podemos gerar diretamente uma tarefa Tokio do nosso <code>Future</code>. Para Dioxus-Desktop, sua tarefa será gerada no tempo de execução Multi-Tarefado do Tokio:</p>
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<pre><pre class="playground"><code class="language-rust edition2018">
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<span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span> cx.spawn(async {
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let _ = tokio::spawn(async {}).await;
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let _ = tokio::task::spawn_local(async {
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// some !Send work
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})
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.await;
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});
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<span class="boring">}
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</span></code></pre></pre>
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